Subsurface back pressure valve apparatus for effecting automatic fluid filling of well casing



2,737,195 US FOR EFFECTING 2 Sheets-Sheet 1 MART/N B. LEA/e40, INVENTORS.

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M rch 6, 1956 R. C. BAKER .ETAL SUBSURFACE BACK PRESSURE VALVE APPARAT AUTOMATIC FLUID FILLING OF WELL CASIN F'iled Dec. 14 1951 REUBEN C. BAKER,

March 6, 1956 R. c. BAKER 'ErAL 2,737,195 SUBSURFACE BACK PRESSURE VALVE APPARATUS FOR EFFECTING AUTOMATIC FLUID FILLING OF WELL CASING File d Dec. 14, 1951 2 Sheets-Sheet 2 g 5: W I 6:

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M M M Anne/v5 1 6 United States Patent Of SUBSURFACE BACK PRESSURE VALVE APPARA- TUS FOR EFFECTING AUTOMATIC FLUID FILL- lNG F WELL CASING Reuben C. Baker, Coalinga, and Martin B. Conrad, Downey, Califl, assignors to Baker Oil Tools, Inc, Los Angeles, Calif., a corporation of California Application December 14, 1951, Serial No. 261,638

15 Claims. (Cl. 137-68) The present invention relates to subsurface well apparatus, and more particularly to apparatus that enables the well bore fluid to enter well casing strings, and similar well conduit strings, as they are lowered in a well bore.

Back pressure valve devices are incorporated in subsurface well casing to prevent return flow of cement slurry, and other fluent substances, into the casing after having been ejected therefrom. Such back pressure valve devices prevent upward flow of fluid into the casing, and, if allowed to close when lowering the casing in the well bore, maintain the casing in an empty, buoyant state. If such an empty casing is run to a comparatively great depth in a well bore filled with liquid, the hydrostatic head of fluid externally of the casing is of such great magnitude as to tend to collapse the lowermost end of the casing inwardly. To guard against this occurrence, it has been the practice to fill the casing string from the top of the well bore to reduce the pressure ditferential acting on the lower portion of the casing string, which is a time consuming and costly operation.

Accordingly, it is an object of the present invention to provide improved and comparatively simple apparatus that permits a string of well casing to fill automatically with the well bore fluid as the casing string is lowered in the well bore, and which embodies a back pressure valve that can be rendered temporarily inefliective to accomplish its purpose of preventing an upward flow of fluids through the apparatus and easing string.

Another object of the invention is to hold a back pressure valve of an apparatus capable of incorporation in a string of well casing from closing, allowing restricted flow of well bore fluids into the casing string while the latter is being lowered in the well bore, the back pressure valve being allowed to close whenever desired, and fluid permitted to flow or be pumped downwardly through the apparatus in a comparatively unrestricted fashion.

lowered in the well bore, the apparatus having a restricted passage precluding rapid filling of the well bore fluid in the casing string, and the valve member being released to engage its seat merely by pumping fluid downwardly in the casing string, which action also effects increase in the effective passage area in the apparatus through which fluids can How.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of several forms in which ,it maybe embodied. Such forms are shown in the drawings accompanying and forming part of the .present specification. These forms will now be described in detail, illustrating the general principles of the inven- 2,737,195 -;Patented Mar. 6, 1956 TCC 2 tion; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a longitudinal section through an apparatus incorporated in a string of well casing, with its back pressure valve held from closing;

Fig. 2 is a view similar to Fig. 1,'disclosing the back pressure valve member released to allow its shifting to closed position;

Fig. 3 is an enlarged fragmentary longitudinal section through part of the structure for holding the back pressure valve member in open position;

Fig. 4 is a cross-section taken along the line 4-4 of Fig. 3;

Fig. 5 is a view similar to Fig. 1 of another embodiment of the invention;

Fig. 6 is a view similar to Fig. 5, disclosing parts of the apparatus in their relative positions following release of the back pressure valve member.

As disclosed in the drawings, the apparatus A forms part of a string of well casing, or similar well conduit, to be lowered in a well bore filled with fluid. Specifically, the apparatus is illustrated as a casing collar adapted to connect upper and lower casing sections B, C in longitudinally spaced relation, although it is to be understood that the apparatus may also be constituted as a casing shoe forming the lower terminus of the well casing string.

The apparatus includes an outer tubular member 10 having upper and lower threaded boxes 11, 12 for threaded attachment to the upper and lower casing sections B, C, respectively. Secured within the tubular member is a cementitious plug 13 which is attached to the tubular member 10 by providing grooves 14 in the latter receiving external ribs 15 that are cast thereinto when the cementitious plug is poured in place. This cementitious plug has a central passage 16 extending throughout its length.

A valve seat 17 is secured in the cement plug '13, this seat being adapted for engagement by a back pressure valve member 18, that may be in the form of a ball made of a material that will cause "the ball to be buoyant in cement slurry. The ball'is'movabl'e upwardly into engagement with the valve seat '17,'to prevent upward flow of fluid through the apparatus A-and into the upper sections B of "the casing string. To prevent fluid leakage between the ball 18 and seat 17, a suitable seal ring 19 maybe mounted'inthe seat for engagement by the ball. V V

The ball valve member 18 is contained within the upper portion 20 of a valve housing 21, which is also cast in the cementitious plug 13. The upper end of this valve housing portion 20 engages the valve seat 17 and also the seal ring 19, to 'hold the latter in the-seat. Its lower portion 22 is of reduced diameter, being fitted within a lower section 23 of 'the valve housing which is cast in the plug 13, a's by having internal ribs 24 of the plug received within longitudinally spaced grooves 25 in the housing section. The lower portion of the lower section 23 has a downward and inwardly tapering stop shoulder 26, that accomplishes a purpose described hereinafter.

Downward movement of the ball valve member 18 within the housing 21 is limited by engagement of the former with a plurality of circumferentially spaced lugs or ribs 27 extending inwardly and preferably integral with the main wall of the upper valve housing section 20. Initially, upward movement of the valvernember 18 into engagement with its companion seat 17 is prevented by a retaining or holding mechanism which may actually hold the ball valve member in a downward position upon the housing ribs. This holding mechanism includes a valve stem 28 having an upper threaded end 29 screwed into a companion threaded bore 3th in the lower portion of the ball 18. The lower end 31 of the valve stem is threaded, being screwed into a central threaded bore 32 in a valve disc 33 disposed within the valve housing 21. This disc has an upper portion 34 piloted within the reduced diameter portion 22 of the upper housing section 20, the disc making a comparatively snug peripheral fit with this housing portion to prevent passage of fluid therebetween. When the disc is in such sealing engagement with the housing portion 22, a lower disc shoulder 35 engages the lower end 36 of the upper housing section (Fig. 1).

During lowering of the string of well casing B, C ernbodying the apparatus A through the well bore, the well bore fluid is allowed to pass upwardly through the apparatus and on into the casing sections B thereabove, by providing one or more longitudinally extending ports or passages 37 through the valve disc. These ports or passages 37 preferably have a restricted area, to throttle the fluid as it flows upwardly through the apparatus, preventing it from entering the casing sections B above the apparatus A at too rapid a rate. Thus, the fluid will flow through the valve disc ports 37 and between the housing ribs 27, continuing on around the ball valve member 18 and up through the central passage 16 in the plug for discharge into the upper casing sections B. it is apparent that the ball valve member 18 is precluded from shifting upwardly into engagement with its seat 17 by its valve stem 23 and the engagement of the valve disc shoulder 35 with the lower end 36 of the upper housing section 22.

The valve stem 28 is provided with a weakened section 38 obtained by substantially reducing the diameter of the stem. Thus, when it is desired to free the ball valve member 13 after the casing string has been lowered in the Well bore to the desired depth, fluid under pressure is pumped downwardly through the casing string B, the disc ports or passages 37, being of restricted area, causing a back pressure to be built up on the upstream side of the disc 33. When this pressure exceeds the tensile strength of the weakened valve stem section 38, the valve stem is pulled apart at such weakened portion, the disc 33 being shifted downwardly until the lower downward and inwardly tapering portion 39 of the disc engages the tapered stop 26 in the lower housing section 23. Disruption of the valve stem 28 frees the ball 18, enabling it to move upwardly into engagement with its companion seat 17, in the event reverse flow of fluids upwardly in the casing section C tends to occur.

It is to be noted that the inside diameter of the lower valve housing section 23 is substantially greater than the diameter of the portion 40 of the valve disc that was piloted within the upper housing section 20. Moreover, diagonal grooves or passages 41 are provided in the lower portion 42 of the valve disc, extending from the periphery of the Valve disc to its lower end 43. Because of this arrangement and the dimensions of the passages or grooves 41, the valve disc 33 has a greater passage area therethrough, and therearound, when engaging the tapered stop 26 in the lower valve housing section 23 than when the valve disc is piloted within the upper casing section 20. Accordingly, after the valve stem 28 has been pulled apart at its weakened section 38, and the valve disc 33 shifted downwardly into engagement with the stop 26, fluids pumped down through the casing string B can flow around the ball valve member 18 and between the lugs or ribs 27, passing down through the ports 37 of restricted area extending through the disc, and also flowing around the periphery 40 of the disc through the comparatively large annular space 45 between the periphery of the disc and the inner wall of the lower housing section 23, this latter fluid then passing through the diagonal passages 41 to the region below the valve disc 33, from where it can flow in a downward direction through the lower casing sections C for discharge from the latter (see Figs. 2 and 3). Any tendency for reverse flow of fluids to occur is precluded by upward shifting of the ball valve member 18 into engagement with its seat and seal ring, as illustrated in broken lines in Fig. 2.

it is, accordingly, apparent that a subsurface well apparatus has been provided, which allows the well fluid to automatically enter the casing string and fill it to the top of the hole, or at least to the level of the well fluid surrounding the casing, the ball valve member 18 being positively held from its seat 17. Such flow of fluid occurs in a comparatively gradual manner because of the restricted area through the passages or ports 37, through which the fluid must pass. As a result, there is less tendency for the fluid filling the casing to flow over its upper end, which tends to wet the derrick floor and make it inconvenicut and hazardous for personnel to operate. However, despite the upward restricted flow of fluid through the valve disc 33, there is no restriction to the downward flow of fluid through the casing string and apparatus, following freeing of the ball valve member 13, since the flow of fluid through and around the valve disc 33 takes place through a passage area that is many times greater than the area of the disc ports 37 themselves.

A modified form of apparatus embodying the invention is illustrated in Figs. 5 and 6. Instead of attaching the ball valve member 18:: positively to the disc 33a, as in the embodiment illustrated in Figs. 1 to 4, inclusive, the disc has an upwardly extending retainer arm 50 integral therewith engaging the side of the ball 18a and holding the latter transversely against the upper valve housing section 20, precluding the ball from moving upwardly into engagement with its companion seat 17. The valve disc 33a and its retaining arm 5i are initially held in the position precluding engagement of the ball with its seat by one or more shear pins or screws 51 extending through the upper valve housing section 20 and the valve disc 33a.

The string of well casing B, C is lowered through the well bore fluid to the desired depth in the hole, the fluid flowing relatively upwardly through the restricted passages 37 in the valve disc 33a, between the ribs or lugs 27 of the valve housing 21, around the ball 18a and through the valve seat 17 and plug passage 16 for upward flow through the upper casing sections B (Fig. 5). As in the other form of the invention, when the casing string has been run to the desired depth in the well bore, fluid under pressure is merely pumped downwardly through the casing string, the valve disc ports 37 causing a back pressure to be built up which, when suflicient in magnitude, overcomes the shear strength of the screws 51, disrupting the latter and shifting the valve disc 33a and its retainer arm 50 in a downward direction, the valve disc coming to rest upon the tapered housing stop 26 (Fig. 6). When in this position, the upper end 52 of the arm 51 has been removed from engagement from the ball valve member 18a, which is now free to move upwardly into engagement with its companion valve seat 17 and seal ring 19, as disclosed in Fig. 6. As fluid, such as cement slurry, is now pumped down through the casing string, it will shift the ball 18a downwardly from engagement with its seat 17, flowing around the ball, between the ribs 27, and down through the disc ports 37, as well as around the disc, for discharge into the casing sections C below the apparatus. As in the other form of the invention, the fluid passage area through and around the disc 33a is many times greater than the area through and around the ports 37, allowing substantially unimpeded flow of the fluid pumped down through the casing string and through the apparatus.

Certain features of novelty disclosed herein are described and claimed in our copending application for Apparatus for Allowing Well Conduits to Pill With Well Bore Fluids, Serial No. 261,639, filed December 14, 1951.

The-inventors claim:

1. In apparatus of the character described: a tubular member adapted to form part of a casing string positionable in a well bore; a valve seat on said member; a valve member movable in a downstream direction into engagement with said seat to restrict flow of fluid through said tubular member; releasable means engageable with said valve member to prevent engagement of said valve member with said seat, said means comprising a valve disc upstream of said valve member and having a fluid passage therethrough of'restricted area to enable back pressure to be built up in said tubular means between said valve member and valve disc to release said releasable means and allow said valve member to engage said seat.

2. In apparatus of the character described: a tubular member adapted to form part of a casing string positionable in a well bore; a valveseat on said member; a valve member engageable with said seat to restrict flow of fluid through said tubular member; releasablemeans engageable with said valve member to prevent engagement of said valve member with said seat, said means comprising a shiftably mounted valve disc having a fluid passage therethrough of restricted area to enable back pressure to be built up in said tubular means to release said releasable means to shift said disc and allow said valve member to engage said seat; and means providing additional passage area within said tubular member through which fluid can bypass said disc following shifting of said disc to release said releasable means.

3. In apparatus of the character described: a tubular member adapted to form part of a casing string positionable in a well bore; a valve seat on said member; a valve housing in said tubular member; a valve member in said housing and engageable with said seat to restrict flow of fluid through said tubular member; releasable means engageable with said valve member to prevent engagement of said valve member with said seat; said means comprising a valve disc in said housing having a fluid passage therethrough of restricted area to enable back pressure to be built up in said tubular member to shift said disc to release said releasable means and allow said valve member to engage said seat; and means providing additional passage area within said'tubular member through which fluid can by pass said disc following shifting of said disc to release said releasable means.

4. In apparatus of the character described: a tubular member adapted to form part of a casing string positionable in a well bore; a valve seat on said member; a valve housing in said tubular member having an enlarged portion; a valve member in said housing and engageable with said seat to restrict flow of fluid through said tubular member; releasable means engageable with said valve member to prevent engagement of said valve member with said seat; said means comprising a valve disc in said housing engaging said housing to prevent fluid from by-passing around said disc and having a fluid passage therethrough of restricted area to enable back pressure to be built up in said tubular member to shift said disc to release said releasable means and allow said valve member to engage said seat; said disc being shifted, in releasing said releasable means, into said enlarged portion of said housing to enable fluid to by-pass around said disc.

5. In apparatus of the character described: a tubular member adapted to form part of a casing string positionable in a well bore; a valve seat on said member; a valve housing in said tubular member; a valve member in said housing and engageable with said seat to restrict flow of fluid through said tubular member; releasable means engageable with said valve member to prevent engagement of said valve member with said seat; said said housing to enable fluid to by-pass around the periphery of said disc.

6. In apparatus of'the'character described: a tubular member adapted to form part of a casing string positionable in a wellbore; a valve seat on said member; a'valve member engageable with said seat to restrict flow of fluid through said tubular member; a shiftably mounted valve disc; frangible means securing said disc to said valve member to prevent said valve member from engaging said seat; said disc having a fluid passage therethrough of restricted area to enable back pressure to be built up in said'tubular member to shift said disc and disrupt said frangible means and allow said valve member to engage said seat.

7. In apparatus of the character described: a tubular member adapted to form part of a casing string positionable in a well bore; a valve seat in said member; a valve member engageable with-said seat to restrict flow of fluid through said tubular member; a shiftably mounted valve disc; a valve stem secured to said valve member and valve disc and having a weakened section; said disc having a fluid passage therethrough of restricted area to enable back pressure to be built up in said tubular member to shift said disc and disrupt said valve stem at said weakened section and allow said valve member to engage said seat.

8. In apparatus of the character described: a tubular member adapted to form part of a casing string positionable in a well bore; a valve seat on said member; a valve member engageable with said seat to restrict flow of fluid through said tubular member; a shiftably mounted valve disc; frangible means securing said disc to said valve member to prevent said valve member from engaging said seat; 'said disc having a fluid passage therethrough of restricted area to enable back pressure to be built up in said tubular member to shift said disc and disrupt said frangible means and allow said valve member to engage said seat; and means providing additional passage area within said tubular member through which fluid can by-pass said disc following disruption of said frangible means.

9. 'In apparatus of the character described: a tubular member adapted to form part of a casing string positionable in a well bore; a valve seat in said member; a valve housing in said tubular member; a valve member in said housing and engageable with said seat to restrict flow of fluid through said tubular member; a valve disc having its periphery substantially sealed by said housing; a valve stem secured to said valve member and valve disc and having a weakened section; said disc having a fluid passage therethrough of restricted area to enable back pressure to be built up in said tubular member to shift said disc to disrupt said valve stem at said weakened section and allow said valve member to engage said seat; said disc being shifted, in disrupting said valve stem, out of sealing relation to said housing to enable fluid to by-pass around the periphery of said disc.

10. In apparatus of the character described: a tubular member adapted to form part of a casing string positionable in a well bore; a valve seat on said member; a valve member engageable with said seat to restrict flow of fluid through said tubular member; a valve disc having a retaining arm; frangible means secured to said disc to hold said arm in a position engageable with said valve member to prevent engagement of said valve member with said seat; said disc having a fluid passage therethrough of restricted area to enable back pressure to be built up in said tubular member to disrupt said frangible means and shift said disc and arm to a position allowing said valve member to engage said seat.

11. In apparatus of the character described: a tubular member adapted to form part of a casing string positionable in a well bore; a valve seat on said member; a valve member engageable with said seat to restrict flow of fluid through said tubular member; a valve disc having a retaining arm; frangible means secured to said disc to hold said arm in a position engageable with said valve member to prevent engagement of said valve member with said seat; said disc having a fluid passage therethrough of restricted area to enable back pressure to be built up in said tubular member to disrupt said frangible means and shift said disc and arm to a position allowing said valve member to engage said seat; and means providing additional passage area within said tubular member through which fluid can by-pass around said disc following shifting of said disc to disrupt said frangible means.

12. In apparatus of the character described: a tubular member adapted to form part of a casing string positionable in a well bore; a valve seat on said member; a valve housing in said tubular member; a valve member in said housing and engageable with said seat to restrict flow of fluid through said tubular member; a valve disc having its periphery substantially sealed by said housing; a retaining arm secured to said disc; frangible means securing said disc to said housing to hold said arm in a position engageable with said valve member to prevent engagement of said valve member with said seat; said disc having a fluid passage therethrough of restricted area to enable back pressure to be built up in said tubular member to disrupt said frangible means and shift said disc and arm to a position allowing said valve member to engage said seat; said disc being shifted, in disrupting said frangible means, out of sealing relation to said housing to enable fluid to by-pass around the periphery of said disc.

13. In apparatus of the character described: a tubular member adapted to form part of a casing string positionable in a well bore; a valve seat on said member; a valve housing in said tubular member; a valve member in said housing and engageable with said seat to restrict flow of fluid through said tubular member; releasable means engageable with said valve member to prevent engagement of said valve member with said seat; said means comprising a valve disc having its periphery substantially sealed by said housing and having a fluid passage therethrough of restricted area to enable back pressure to be built up in said tubular member to shift said disc to release said releasable means and allow said valve member to engage said seat; means engageable with said valve member to limit its movement in a direction away from said valve seat; said disc being shifted, in releasing said releasable means, out of sealing relation to said housing to enable fluid to by-pass around the periphery of said disc.

14. In apparatus of the character described: a tubular member adapted to form part of a casing string positionable in a well bore; a valve seat on said member; a valve member engageable with said seat to restrict flow of fluid through said tubular member; a shiftably mounted valve disc; frangible means securing said disc to said valve member to prevent said valve member from engaging said seat; means engageable with said valve member to limit its movement in a direction away from said valve seat; said disc having a fluid passage therethrough of restricted area to enable back pressure to be built up in said tubular member to shift said disc and disrupt said frangible means and allow said valve member to engage said seat.

15. In apparatus of the character described: a tubular member adapted to form part of a casing string positionable in a well bore; a valve seat in said member; a valve housing in said tubular member; a valve member in said housing and engageable with said seat to restrict flow of fluid through said tubular member; a valve disc having its periphery substantially sealed by said housing; a valve stem secured to said valve member and valve disc and having a weakened section; means engageable with said valve member to limit its movement in a direction away from said valve seat; said disc having a fluid passage therethrough of restricted area to enable back pressure to be built up in said tubular member to shift said disc to disrupt said valve stem at said weakened section and allow said valve member to engage said seat; said disc being shifted, in disrupting said valve stem, out of sealing relation to said housing to enable fluid to by-pass around the periphery of said disc.

References Cited in the tile of this patent UNITED STATES PATENTS Re. 22,483 Burt May 23, 1944 2,178,845 Baker Nov. 7, 1939 2,373,005 Baker Apr. 3, 1945 2,471,383 Althouse, Jr., et al May 24, 1949 2,647,584 7 Baker Aug. 4, 1953 FOREIGN PATENTS 209,821 Great Britain 1924 

